I'm thinking about buying a 1997 - 72 passenger International-Genesis with a mechanical DT466, but I can't for the life of me find the model of the tranny to confirm it's a MT643 or newer? I crawled under and looked on the passenger side for the metal tag and no luck. I called the mechanic at the bus shop, and he said he believes it was a 3000 series Allison. I can't help but doubt that on a 1997? Any ideas?